An inscription found in Turkey written by Persian king Xerxes that’s 25 centuries old According to a recent post by the BBC , historians estimate that 1% of material in libraries and archives worldwide is fully or partially encrypted. That sounds modest until you consider the scale of what it represents: assassination plots, love letters, medical secrets, diplomatic intelligence, the inner workings of organizations that could not afford to be discovered. Some of these documents have been sitting unread for centuries: A 408-page Vatican manuscript sat unread for more than 400 years. A letter from the most powerful man in 16th-century Europe went uncracked for nearly 500. A philosopher’s treatise on pleasure , buried under volcanic ash in 79 CE, waited almost two millennia. Across the world’s archives, an extraordinary amount of human history has been sitting in silence. Not exactly lost but locked.…